Compact flash cards (CF cards) are size compatible with the current state of the art in wireless cards. Present technology allows integration in form factors much smaller than the previous generation of PCMCIA cards. However, few compact flash cards have been introduced to the market that are designed to work over Wireless Wide Area Networks (WWAN). One of the main reasons is that the CF interface is specified to allow only 500 mA maximum current to be drawn across a power interface and CDMA, for example, requires up to 850 mA. Thus, a wireless card cannot operate on the same power interface as the CF card.
It is possible to utilize an external battery to provide the additional power required by a wireless card, but for a reasonable capacity, the size of the battery can easily be larger than the size of the wireless card, defeating the purpose of having a smaller CF form factor.
Accordingly, there is a need to provide a system and method for maintaining a battery and sharing the stored charge with the supply from the CF card power interface in order to provide power for a wireless card.